is it just me or is even the full prompt still incomplete thus nonsensical?

It's probably not just you as I've misread it a few times now and I'm the one who wrote it. I intended it to mean "Most people are too often overconfident that they know what someone else is trying to say. It can be helpful in discussions to take a step back and check whether you are actually [interpreting what they are saying how they meant it to be interpreted]" specifically it's a reference to the double illusion of transparency and basically all of Duncan Sabien's guidelines for rationalist discourse. Yeah, reading it again it doesn't really make sense. I think it might have originally said 'understand' instead of 'know' and then I changed it not realizing that would change the meaning of the second sentence too. Thanks for clarifying.

Thanks, maybe a more concise phrasing would be "People are often overconfident that they know what someone else is trying to say, so it can be helpful to check whether you are accidentally doing the same"